1. Field of the Invention
This invention relates to a releasable drive used to power a room actuating mechanism which extends and retracts a slide-out room of a recreational vehicle.
2. Description of the Related Art
Recreational vehicles often include a slide-out room which is movable between extended and retracted positions. The slide-out room remains retracted during transit of the vehicle and is extended when the vehicle is parked to increase the usable floor space within the vehicle. Movement of the slide-out room is usually accomplished by an electric motor acting through a gear drive. The gear drive is often provided with a manual back-up, such as a crank handle, which can be used to retract or extend the room in case of loss of electric power or other failure of the electric motor.
A problem with current gear drives is that the electric motor remains engaged with the gear drive when the manual back-up is being employed. Therefore, as an operator turns the crank handle, the motor is also being turned. The motor thus provides resistance to the operation of the manual back-up which makes it more difficult for the operator to turn the crank handle.
Another problem with current gear drives occurs if the internal geartrain of the gear drive becomes damaged, such as if teeth are sheared off of one of the gears. Under these circumstances, it may become impossible to move the slide-out room using either the motor or the manual back-up. This can present a particularly awkward problem if the room is extended and the vehicle must be removed.
What is needed is a release mechanism for a gear drive which allows the operator to disconnect the motor and the internal geartrain of the drive when the manual back-up is being used. This will make the crank handle easier to turn under all operating conditions, and will allow the manual back-up to operate even if the geartrain becomes damaged.
The present invention comprises a drive assembly for a slide-out room of a recreational vehicle. The drive includes a gearbox containing a drive train with at least a drive gear and an output gear. An electric motor is connected to the drive gear. The output gear has a center hole formed therethrough which receives a drive shaft. The drive shaft is movable relative to the output gear in opposed first and second longitudinal directions. A drive member connected to a first end of the drive shaft is engageable with a room actuation mechanism and a second end of the drive shaft is engageable by a crank handle for manual operation of the room actuation mechanism.
A clutch connected to the drive shaft is operable to engage the drive shaft with the output gear as the drive shaft is moved in the first longitudinal direction and disengage the drive shaft from the output gear as the drive shaft is moved in the second longitudinal direction. The clutch may comprise a pin extending radially outward from the drive shaft acting in cooperation with a notch formed in a face of the output gear so as to extend radially outward from the center hole. The pin is receivable within the notch to engage the drive shaft with the output gear.
Three embodiments of the invention are disclosed, each of which includes a shift mechanism for selectively moving the drive shaft between an engaged position wherein the drive shaft is engaged with the output gear and a disengaged position wherein the drive shaft is disengaged from the output gear.
In the first embodiment, the shift mechanism includes a washer fixedly attached to the drive shaft so as to extend radially outward therefrom and a spring biasing the drive shaft in the second longitudinal direction. A shift block is slidably mounted adjacent the drive shaft and includes a transverse groove which receives a portion of the washer. A jack screw connected to the shift block is operable to selectively move the shift block in the first and second longitudinal directions. By turning the jack screw in a first rotational direction, an operator can causes an edge of the groove to engage the washer and move the drive shaft in the first longitudinal direction against the bias of the spring, thereby causing the pin in the drive shaft to disengage from the output gear. Conversely, by turning the jack screw in a second rotational direction opposite the first rotational direction, the operator can allow the spring to urge the drive shaft in the second longitudinal direction, thereby causing the pin to re-engage the output gear.
The second embodiment of the invention also includes a washer fixedly attached to the drive shaft so as to extend radially outward therefrom. A shift lever is mounted adjacent the drive shaft for pivotal movement about its proximate end. An opening having opposed, inwardly curved, edges is formed in the shift lever. The opening receives a portion of the washer. Pivoting the shaft lever in a first direction moves the drive shaft in the first longitudinal direction causing the pin in the drive shaft to disengage from the output gear. Pivoting the shift lever in a second direction opposite the first direction moves the drive shaft in the second longitudinal direction causing the pin to re-engage with the output gear. The device further includes a latch plate having a first notch and a second notch, the first notch engages a portion of the shift lever when the drive shaft is in the engaged position and the second notch engaging a portion of the shift lever when the drive shaft in the disengaged position.
In the third embodiment, the shift mechanism includes a washer fixedly attached to the drive shaft so as to extend radially outward therefrom and a spring biasing the drive shaft in the second longitudinal direction. A shift block is slidably mounted adjacent the drive shaft and includes a bore which slidably receives the drive shaft. A threaded rod connected to the shift block is engaged by a nut operable to selectively move the shift in the first and second longitudinal directions. By turning the nut in a first rotational direction, an operator can causes an edge of the shift block to engage the washer and move the drive shaft in the first longitudinal direction against the bias of the spring, thereby causing the pin in the drive shaft to disengage from the output gear. Conversely, by turning the nut in a second rotational direction opposite the first rotational direction, the operator can allow the spring to urge the drive shaft in the second longitudinal direction, thereby causing the pin to re-engage the output gear.